Dr. Joseph Mercola is an osteopathic physician specializing in non-mainstream treatment.
He has long been critical of vaccines and has identifies that compounds such as thimerosal are harmful because of their Mercury component.
Recently, he correctly identified the efficacy of Vitamin C, Vitamin D3, and Quercetin against COVID-19, which resulted in an FDA warning letter. This is the same combination of products that is successful and advocated by the Front Line COVID-19 Critical Care Alliance (FLCCC) group.
His website contains a large amount of biographical information.